Table of contents
1.
Introduction
2.
What is DynamoDB?
3.
What is DynamoDB TTL?
4.
How to set TTL in DynamoDB?
4.1.
TTL Set up Using Command Line Interface (CLI)
4.2.
TTL Set up Using Cloud Development Kit (CDK)
4.3.
JavaScript
4.4.
TTL Set Up Using AWS Console
5.
Frequently Asked Questions
5.1.
How can I set a custom TTL value in DynamoDB?
5.2.
How does TTL (talk-to-live) feature affect the performance and efficiency of the system?
5.3.
Can we recover the data from expired and deleted items with the TTL method?
6.
Conclusion
Last Updated: Mar 27, 2024
Medium

DynamoDB TTL

Author Aayush Sharma
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Introduction

In today's scenario, everything is fast-paced and efficient. Data management is also required to be more efficient and automated. The need to delete outdated or expired data from the database system arises from the sheer volume of data. For any system, memory is a crucial resource. The cost of memory that meets the requirements rises exponentially when the criteria start to rise. Thus, we need to take care that the system doesn't include any redundant data. DynamoDB solves this problem using its TTL (time-to-live) attribute.

dynamodb ttl

In this blog, we will discuss DynamoDB TTL in detail. We will study the TTL (time-to-live) attribute in detail. We will also discuss the various methods to set the TTL feature in our DynamoDB instance. But first, let us learn more about DynamoDB and its TTL attribute in detail in the next section.

What is DynamoDB?

DynamoDB is a NoSQL database provided by the Amazon Web Service (AWS).It is a scalable database system used to meet the needs of online services and applications. The user can manage massive amounts of organised, semi-structured, and unstructured data using DynamoDB's storage environment.

dynamodb logo

Like any other NoSQL database, DynamoDB also possesses many valuable features. Some of the promising features of DynamoDB are given below.

  • Flexibility - DynamoDB stores data in a JSON-like structure, increasing the data's flexibility. The data's design can be changed dynamically whenever required.
     
  • Horizontal Scalability - DynamoDB provides horizontal scaling in the database system. This means that we can use multiple servers to handle large amounts of traffic and increase the fault tolerance of a system.
     
  • Security Features - DynamoDB provides users with many security features like authentication, authorization, encryption, etc., to protect the data from unauthorized access.
     
  • Community - DynamoDB is a popular database with a large user community, making resolving queries for new people easy.
     
  • Easy Integration - DynamoDB can easily integrate with AWS services like AWS Lambda, Amazon Kinesis, Amazon CloudWatch monitoring, etc.

What is DynamoDB TTL?

TTL stands for time-to-live. DynamoDB allows the users to specify a time-to-live timestamp attribute to define when the database needs any item. In simpler terms, the TTL attribute tells DynamoDB to remove the items whose TTL attribute has crossed the current timestamp.

The DynamoDB TTL attribute allows the users to define a timestamp in the epoch timestamp format. This timestamp indicates when a particular item will expire. Once the TTL of any item expires, it is removed from the table and deleted from the database.

Time-to-live is a helpful mechanism to remove unnecessary items such as session cookies. This data type is unnecessary for us after a certain amount of time. AWS prices the user based on memory usage. If we do not remove such unnecessary data from the system, it can lead to additional costs which could be printed.

One great example of TTL is the shopping carts on online shopping platforms. If any item goes out of stock, it is removed automatically from the shopping cart. This feature can be easily implemented by using TTL. The TTL attribute can be set in such a way that if the stock quantity goes to zero, it gets deleted from the table.

How to set TTL in DynamoDB?

So now that we know about the TTL attribute in detail, we will now discuss the different methods to set up the TTL attribute in DynamoDB.

TTL Set up Using Command Line Interface (CLI)

The first method to set up the TTL attribute is by using the command line interface. We can use the command update-time-to-live in the command line to set up the TTL flag.
 

aws dynamodb update-time-to-live \
–table-name sampleTable \
–time-to-live-specification "Enabled=true, AttributeName=ttl"


After using the above command in the command line, the TTL attribute will be automatically set in DynamoDB.

TTL Set up Using Cloud Development Kit (CDK)

Another popular method to set up the TTL attribute is to specify the TTL attribute during creation. We just need to set our timeToLiveAttribute to the required value.
 

  • JavaScript

JavaScript

const sampleTable =new DynamoDB.Table(this, "sampleTableTTL", {
billingMode: BillingMode.PAY_PER_REQUEST,
partitionKey: {
Name: "pk",
type: AttributeType.STRING,
},
timeToLiveAttribute: "ttl",
})
You can also try this code with Online Javascript Compiler
Run Code


This will enable the TTL attribute for the table.

TTL Set Up Using AWS Console

If you want to manually set the TTL attribute instead of using the Command Line Interface, you can do it with the help of AWS Console.

console view

You can set the TTL attribute by using the Manage TTL button in the Time to Live attribute section.

Frequently Asked Questions

How can I set a custom TTL value in DynamoDB?

It is possible to set any custom value to the TTL (time-to-live) feature in DynamoDB. We can set the TTL value by providing a Unix Timestamp in the TTL attribute during setup.

How does TTL (talk-to-live) feature affect the performance and efficiency of the system?

The TTL feature in DynamoDB does not significantly impact the system's performance. But it helps optimize the storage for queries and helps in easier maintenance of the system DB.

Can we recover the data from expired and deleted items with the TTL method?

It is not possible to recover an item after its expiration. Once a time expires on the basis of TTL expiration, it is permanently deleted from the table and hence cannot be recovered.

Conclusion

In this article, we discussed DynamoDB TTL. We discussed DynamoDB and DynamoDB TTL in detail. We also looked at the various methods of setting up TTL in DynamoDB. In the end, we concluded by discussing some frequently asked questions related to DynamoDB TTL.

So now that you know about DynamoDB TTL, you can refer to similar articles.

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